Aggregate Behavior and Microdata

It is shown how one can effectively use microdata in modelling the change over time in an aggregate (e.g. mean consumption expenditure) of a large and heterogeneous population. The starting point of our aggregation analysis is a specification of explanatory variables on the micro-level. Typically, some of these explanatory variables are observable and others are unobservable. Based on certain hypotheses on the evolution over time of the joint distributions across the population of these explanatory variables we derive a decomposition of the change in the aggregate which allows a partial analysis: to isolate and to quantify the effect of a change in the observable explanatory variables. This analysis does not require an explicit treatment of the unobservable variables.

Aggregation under structural stability: the change in consumption of a heterogeneous population

It is shown how one can effectively use cross-section data in modelling the change over time in aggregate consumption expenditure of a heterogeneous population. The starting point of our aggregation analysis is a dynamic behavioral relation on the household level. Based on certain hypotheses on the evolution of the distribution of income and household characteristics we derive explanatory variables for the change in aggregate consumption expenditure which are quite different from the explanatory variables on the household level. It is shown that U.K. Family Expenditure Data support our theoretical model for aggregate consumption.

Pionic Final State Interactions and the Hypertriton Lifetime

We analyze the contribution of pionic final state interactions (FSI) in the weak decay of the hypertriton. Focusing on the $^3$He channel, we find a contribution of the pionic FSI of the order of $18\%$. Assuming a fixed value for the branching ratio $R_3$ for the decay width into $^3$He over the decay width into $^3$He and $pd$ final states, we find values for the hypertriton lifetime that are consistent with the world average as well as recent measurements by the ALICE Collaboration.Comment: 11 pages, 4 figure

Bis[bis(trimethylsilyl)methyl]gallium bromide and monomeric {bis[bis(trimethylsilyl]methyl]gallium} [tris(trimethylsilyl)silyl]telluride [(Me3Si)2CH]2Ga–TeSi(SiMe3)3

Bis[bis(trimethylsilyl)methyl]gallium bromide GaBr[CH(SiMe3)2]2 (4), prepared from Ga2Br4 · 2 dioxane and bis(trimethylsilyl)-methyllithium in the molar ratio of 1:3, reacts with the sterically high-shielded lithium tris(trimethylsilyl)silyltelluride · DME to yield [(Me3Si)2CH]2Ga–TeSi(SiMe3)3 (5). 5 can also be synthesized by a metathetic reaction between tetrakis-[bis(trimethylsilyl)methyl]digallium(4) and bis[tris(trimethylsilyl)silyl]ditellane in toluene at 100°C. A crystal structure determination shows the compound to be monomeric in the solid state and the atoms of the central C2Ga–TeSi moiety to lie in the mirror plane of the molecule. The short Ga–Te distance of 253.5(1) pm as well as a hindered rotation (ΔErot ≈ 50 kJ · mol-1) as detected by NMR measurements might be interpreted in terms of a π interaction between gallium and tellurium

An exposition of Wald's existence proof

SIGLEAvailable from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, D-21400 Kiel W 45 (546) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Francis Ysidro Edgeworth: perfect competition and the core

SIGLEAvailable from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel W 45 (385) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman